Comparative Evaluation of Dexmedetomidine and Dexamethasone as an Adjuvant to Bupivacaine in Supraclavicular Brachial Plexus Block for Upper Limb Surgeries

Background: Supraclavicular brachial plexus block is commonly used for upper limb surgeries. Various adjuvants have been added to local anaesthetics to improve block characteristics and prolong postoperative analgesia. Dexmedetomidine and dexamethasone are frequently used additives to bupivacaine, but their comparative efficacy remains an area of interest. Methods: This ambispective randomised double-blind controlled study was conducted in 60 adult patients (ASA I–II) undergoing elective upper limb orthopaedic surgeries. Patients were randomly divided into two groups of 30 each. Group A received 25 ml of 0.25% bupivacaine with dexamethasone 8 mg, while Group B received 25 ml of 0.25% bupivacaine with dexmedetomidine 1 µg/kg for ultrasound-guided supraclavicular brachial plexus block. Onset and duration of sensory and motor block, sedation score, haemodynamic variables, time to first rescue analgesia, and total analgesic consumption over 24 hours were recorded and analysed. Results: Dexmedetomidine significantly hastened the onset of sensory (6.4 ± 1.3 min vs 9.8 ± 1.5 min) and motor block (8.1 ± 1.4 min vs 12.2 ± 1.6 min) compared to dexamethasone (p < 0.001). Duration of sensory block (10.2 ± 1.3 hrs vs 7.6 ± 1.1 hrs) and motor block (9.1 ± 1.1 hrs vs 6.3 ± 1.0 hrs) were also prolonged in the dexmedetomidine group (p < 0.001). Time to first rescue analgesia was longer (12.7 ± 1.4 hrs vs 9.8 ± 1.2 hrs), and analgesic requirement over 24 hours was significantly reduced. Sedation scores were higher with dexmedetomidine. Mild bradycardia and hypotension occurred more frequently with dexmedetomidine but were manageable. Conclusion: Dexmedetomidine is a superior adjuvant to dexamethasone when combined with bupivacaine for supraclavicular brachial plexus block, providing faster onset, prolonged block duration, improved postoperative analgesia, and acceptable haemodynamic stability.